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So this is kind of a general info/knowledge question. For those of us who have the old 90 degree inlet setup, how does one update to the modern inlet setup of Intake->inlet hose-> turbo If you update to a non 90 degree inlet turbo. Can you reuse your Ej20g/ej22t Maf sensor and plug it into the modern intakes?

Silicon adapter is the most common. With that you run basically stock stuff up to the adpater.

If your running phase 1 DOHC heads you could swap to an EJ20K (or Legacy twin turbo EJ20H/R) intake manifold and run a full under-the-manifold intake tract. Yes, an EJ20G/EJ22T MAF will bolt to a later airbox. But not too late, they started building them into the filter housing at some point (GD+?).

To be totally honest with you, I really don't understand why you are looking at doing this. You've finally got your car running and you're going to go back in there and F-around with it again? I would be thinking you would want to enjoy it at this point. Have you even driven the car yet? I think with the work we did to it, you won't barely "recognize" the car when you drive it.

That said, if you are serious about using a newer turbo with a straight inlet AND a FMIC as you keep mentioning here and there what you want to do is get a rotated kit. This solves the inlet issue simultaneous to the FMIC. It's the cleanest and easiest install. If you contact Troy at Suba in Denver, he can put something together for you.

To be totally honest with you, I really don't understand why you are looking at doing this. You've finally got your car running and you're going to go back in there and F-around with it again? I would be thinking you would want to enjoy it at this point. Have you even driven the car yet? I think with the work we did to it, you won't barely "recognize" the car when you drive it.

That said, if you are serious about using a newer turbo with a straight inlet AND a FMIC as you keep mentioning here and there what you want to do is get a rotated kit. This solves the inlet issue simultaneous to the FMIC. It's the cleanest and easiest install. If you contact Troy at Suba in Denver, he can put something together for you.

you misread my intentions I was just seeing on RS25 some people were switching to this kind of setup and i was just wondering how it works, as i've never seen a Ej20k side by side with a Ej20g. Truly just to better inform myself, nothing more to it.

I just want to be more knowledgeable about the different subaru turbo offerings throughout the year, and be able to differentiate between their nuances. Just want to expand my knowledge base.

Asside from the superior Ej20k nissan MAF sensor, was there any real benefit for subaru in doing away with the 90 inlet? It seems like having your intake right over your engine isn't exactly going to do wonders for the intake air temp.

As for more power, that is so far down my list, i'm not even sure i'm even going to address that in ~ 2 years.fixing those god awful 5zigen springs and revamping the suspension along with dericing the exterior/repaint are far higher on my to do list.

I greatly appreciate the work you guys did - i haven't returned yet, but my stepbrother did a little lap around the block, and it was great from what i was told. now to find dumpster for that ****ty C west bumper.

Hey cool, Somebody made a thread about this, i was about to do it myself.
I'm still in the planning phase of this project and have not decided yet if its actually going to happen.
I have a spare 98 EJ20G with bad compression, so I want to find a way to work it out to my advantage.

The problems I've run into so far are these:

-Throttle body: its turned 180, so the cable has to come in from the other side,I think worst case on this one is a WRX cable.

- TPS: its a 3 pin as opposed to 4 (i think its just missing the idle switch) might have to retro fit the TB with the old TPS

-MAF : as stated earlier in the thread, MAF fitment will need to be adressed.

-Intercooler clearance : this is my main concern right now. I have a WRX intercooler that I was going to use with this setup, but after just holding it up to the motor, I can see that it definitely won't fit, even with the Bypass valve port blocked off and a differnt valve used, the protrusion for the BPV still hits the IACV. I can space the intercooler further back from the TB with a longer TB to IC hose, since there is about 1.5" more clearance on the V3 20g than the v2, but that may give me a firewall clearance issue.
A though I had to remedy this was, if compatible, use a 2002 WRX TB and IAC and put a plate over the external IAC location to gie me room for the intercooler and BPV.
I have yet to verify if the WRX TB would even bolt on to the 20G/20K manifold, or if the ECU could control the IAC (though the wires seem to have the same roles).

the second option I considered, was to cut off the BPV flange so the IC is flush along that edge, then weld it up and put a 90 deg elbow on it (essentially making a 20K IC)
but I really don't want to cut up an intercooler.
last issue is
-turbo: i'd be giving up a 16g in favor of a TD04L, I don't have money for a better turbo, and while I'd really like to try out a TD04, I don't think I would want to do so much irreversable work for an expreriment that ultimately leaves me with a power deficit.

ok, if the EJ20K is 97+, the JDM dash i got with my clip (V4 STi) is the same as the 93 dash i pulled out of a junkyard, except for the whole RHD part. did they not change the dash like they did in the US?

ok, if the EJ20K is 97+, the JDM dash i got with my clip (V4 STi) is the same as the 93 dash i pulled out of a junkyard, except for the whole RHD part. did they not change the dash like they did in the US?

I'm converted. I just have the EJ20H intake manifold installed on my EJ20G heads, mostly because I couldn't find an EJ20G manifold. There are a couple of different ways that you can do it but they all work.

Now I did mine a little for simple. I ditched all of the stock breather and PCV stuff and I am doing a custom "catch can" that is a Mann Provent 200 Air/Oil separator from a diesel truck. There are a lot of threads on it if you are interested.
I also ditched the recirc valve and went with an atmospheric BOV that bolts directly to my 2006 WRX TMIC. There are issues with an atmospheric BOV of course but that is for another thread...
For the throttle body I had to flip it upside down and rotate the TPS 180' like Slodrive did but instead of making some crazy spacer/adapter plate to get the TB to bolt onto the manifold I just took an angle grinder and made some clearance for it to fit! Mine works without a problem and I don't get why he went through the trouble of making the adapter plate...

Here is the boot he used:
I used a different one but it's made by the same company "Autobahn88" on Ebay. They have two different designs. His is made especially for the EJ20H, mine is made for a GC8 WRX. Because I changed my breather and recirc valve setup the GC8 WRX one works better. They both will fit the same under the manifold though, no problem there.

After the inlet you could go with the rest of the WRX intake if you wanted or basically anything you want. I plan on bringing my filter in from behind the passenger side headlight and deleting the ABS pump that is in the way there. Then building a little divider wall with some thin sheet metal (bends easy and cuts with tin snips) and putting some RV weather stripping on it to get it to seal against the frame and hood and then cutting a hole in the hood and installing one of those generic vents. So it's basically a poor man's version of a cold air intake box. I could bring the air in from the fender which is just as good but it makes it harder to check and clean the filter and this is a rally car. I also could put the filter somewhere higher up on the car so it doesn't get water logged as easily but I think that I'll try this and it should be ok.

As far as the MAF sensor goes I haven't decided if I am going to just delete it and create a map using a MAP sensor and IAT sensor, or if I want to keep the MAF for when the car is not under boost and just use the MAP sensor when there is positive intake manifold pressure. I guess I'll try both and see how well the ECU responds to it. I am using Greddy E-Manage Ultimate. I've heard nothing but good things about the MAP it's just harder to tune.

i think it was either 96 or 97 the dash was altered a bit, the top was convex instead of concave and I believe they all had the passenger side airbag.

out of curiosity, how does that late ej20g TD04L stack up to the US spec WRX version?

I think I'm going to hold off on this conversion for a while.
when i do get around to it, my primary goal is to get it running and looking as close to oem as possible.

i think he was talking about the japan dash, as the dash that came with my EJ20K (should be out of a 97/98 right?) is still convex with no airbag as my 97 coup had the concave with airbag, but im converting to a USDM 93 dash as its concave like the JDM and has no airbags (swappin to the JDM steering column as well so no airbags there now either).

So i borrowed a WRX throtle body and bolted it one to msee what the clearance would be like, fits like a dream, the only interference is with the IAC pipe that goes over the manifold, that would be removed, and the throttle plate rotates the opposite direction, but i cannot forsee that being an issue. the bigger problem is as I had anticipated, different input signals for the IAC, ej20g being dc 6-9 v open closed to open on 2 wires, and ej205 being 0-14v waveform signal on one wire. I may not be clever enough to make that work with a reasonable amount of effort.